Research on force and position control performance of the tendon sheath system with time‐varying parameters and flexible robotic arms

Background The tendon‐sheath‐system (TSS) is an excellent medium for remote power transmission, which is widely used in laparoscopic surgery robots. Since the operation process requires the robot to move continuously, this time‐varying characteristic further aggravates the force and position transmission loss caused by the nonlinear friction of TSS, which affects the control accuracy of the surgical robot. Method A time‐varying tendon‐sheath transmission model (RT model) is proposed. A feedforward control system is designed to improve tendon‐sheath transmission accuracy. Furthermore, a tendon‐sheath transmission model with velocity characteristics (RV model) is established. Result Force, position, and velocity experiments were carried out on the platform of TSS with a robotic arm. The results show that the R‐square values of force and position compensation are at least 96.57% and 99.16%. Conclusion The proposed RT and RV models are effective in compensating for the TSS transmission loss during the operation of the surgical robot.